Two flight attendants on the Asiana Airlines plane that crash-landed were sucked from the plane and thrown down the runway upon impact, crash investigators said today.

"Two flight attendants were ejected from the aircraft during the impact sequence so they were not at their stations when the aircraft came to rest," National Transportation Safety Board Chairwoman Deborah Hersman said at a news conference this evening.

"They were found down the runway and off to the side of the runway," she said. "Those flight attendants survived, but they obviously had gone through a serious event and have injuries."

Hersman also said that, according to interviews with crew members, the plane was "sent into a 360 degree spin" when it crash landed.

Of the three pilots in the cockpit at the time of the crash, the first officer was hospitalized and released with a cracked rib and the other two were not admitted to a hospital.

Hersman said that the pilot flying in the left seat was about halfway through his initial operating experience on the Boeing 777. He was experienced on other types of aircrafts.

The instructor pilot in the right seat "reported that this was his first trip as an instructor pilot," Hersman said. It was the first time the two had flown together.

Meanwhile, the camp that the two teenage girls who died in the crash were supposed to attend with a group of 35 Chinese students and chaperones has been canceled in wake of the crash.

The group was on its way to a three-week summer camp at West Valley Christian Church in Los Angeles. They were going to stay with host families, study English, sight-see, visit universities and explore career opportunities.

"These are amazing, amazing gifted, talented, great prospects with a lot of talent that are coming over here," West Valley Christian School administrator Derek Swales told ABCNews.com today. "It's just devastating to think that superstar kid in the classroom with all that potential was just taken."

The two fatalities were identified as Wang Linjia and Ye Mengyuan, both 16 and students from China. The students had been in the rear of the aircraft, where many of the most seriously injured passengers were seated, NTSB chairman Deborah Hersman said.

Swales said the camp session has been canceled and the remaining students and chaperones are expected to return to China. He does not know if three other scheduled camp sessions with groups from Asia will go on.

The school is planning a vigil and is collecting money that they say will be sent with care packages directly to the families involved.

Meanwhile, why the crash occurred and who is to blame are the focuses of the safety investigation. The National Transportation Safety Board has been meeting with the four pilots of the Asiana Airlines jet that crash-landed at San Francisco Intentional Airport Saturday.

The NTSB is expected to provide more information on the pilots at a news conference later today.

Federal investigators have yet to indicate whether the crash can be attributed to pilot error, while they continue to analyze data recovered from the plane's black boxes.

Investigators have said Flight 214 was flying "significantly below" its target speed during approach when the crew tried to abort the landing just before the plane smashed onto the runway.

The investigation into the cause of the crash has noted that the pilot in charge of the flight was in his ninth training flight on the Boeing 777 and was 11 flights short of the worldwide standard to get licensed, according to company officials.

Pilot Lee Kang-kook had 43 hours of flight experience on the Boeing 777 and Saturday was his first time landing at the airport with that kind of aircraft, Asiana Airlines spokeswoman Lee Hyo-min said Monday at a news conference in Seoul, South Korea.

As authorities continue to investigate the Asiana flight, a Japan Airlines Boeing 777 en route to San Francisco early this morning had to return to Tokyo's Haneda airport after a warning flashed in the cockpit saying the jet's hydraulic fluid level was low, according to the airliner.

The parents of the two Chinese teens killed in Saturday's crash arrived overnight at San Francisco International Airport. An investigation is underway to determine whether one of the two dead girls might have been hit by a rescue vehicle in the chaos after the plane crash-landed.

Hersman said investigators watched airport surveillance video Monday to determine whether an emergency vehicle hit one of the students. But they have not reached any firm conclusions. A coroner said he would need at least two weeks to rule in the matter.

Thirty-seven patients remain hospitalized at San Francisco area hospitals with eight still in critical condition.

Asiana Airlines Flight 214 was carrying 291 passengers and 16 crew members when it crashed. The tail was torn off as it crashed, and it burst into flames. More than 180 people were initially taken to local hospitals for treatment.